As cities grow, open spaces, trees and other greenery, and other naturally occurring surfaces diminish, replaced by concrete and asphalt surfaces. When this happens, the heat absorbed by these surfaces has nowhere to go, and so is radiated and reflected into the immediate surrounding areas. This creates an urban heat island.

This leads to an increase in heat in the immediately surrounding areas, making temperatures a few degrees hotter than the actual weather. This causes discomfort to residents of the area and can also incur damage in the form of heat-damaged structures.

There is also a human cost associated with urban heat islands. Heat-related medical emergencies such as heat stroke become more prevalent in such areas as the heat can go up to dangerous levels. The EPA has taken stock of this phenomenon and is now advising cities to take steps to mitigate it. One such way is the use of Los Angeles solar as a means of making cities cooler and more comfortable to live in.

How does solar minimize this effect?

Cool Roof Strategy

A cool roof strategy is a one that seeks to use heat absorbing and/or dissipating roofing materials and technologies. Typical roofs use materials that either reflect or absorb and radiate back heat. Conversely, cool roofs, like solar, can help absorb sun rays and convert them into beneficial energy.

Solar excels at this because of the way the cells are designed and organized to absorb the maximum amount of sunlight. Solar roofs are also designed to trap this heat rather than radiate it back into the environment, something that can help reduce the amount of secondary heat being released into the environment.

Reduced Construction

When solar roofs are implemented, there is usually a reduced need to construct structures that support the traditional electric grid. Such a scenario can play out in several ways. If a new estate is being built with nothing but solar power, there is a possibility that some open spaces can be retained as fallow ground in places where utility implements would have been installed.

While the gains at this level would be marginal, implementation of this strategy across several thousand estates can help move the needle in reducing the urban heat island effect.

Combination Approach

This approach offers the greatest promise of reducing heat in urban settings. By combining the cool roof strategy with other strategies like green roofing, planting more trees and vegetation, cool paving and general smart city growth, a lot of ground can be covered.

Planting more trees and vegetation will go a long way in reducing heat in urban settings.

All these strategies have one thing in common in that they all absorb and dissipate heat in an efficient and sustainable manner. The EPA recommends these measures, among others, to cities grappling with the urban heat island effect or anticipating it as open spaces and greenery levels go down.

Many cities have a high incentive to deal with this issue because of its effect on residents and visitors to the area. If street-level temperatures are unbearable, it is possible that tourists and potential new residents may shy away from the area in favor of other cooler cities.

Around 5% of the world’s CO2 emissions are caused by concrete production, so finding sustainable alternatives is essential to slowing down climate change. Fortunately, there are plenty of materials out there which are perfect for mass home construction, without the same ecological damage. If you want to continue to do meaningful things, such as travel the world or live in safe and comfortable accommodation, then finding alternative building materials is the route to doing this sustainably.

Hemp Concrete Substitute

By compacting hemp and lime, it is possible to create a building block comparable to concrete. Unlike concrete, however, hemp absorbs carbon dioxide rather than emits it. This means that during the production process, 1m3 of hemp concrete wall will suck up 165kg of CO2. It is just as durable and robust as regular concrete, but will require cannabis legalisation before manufacture can begin.

Nigerians are building fireproof, bulletproof, and eco-friendly homes with plastic bottles and mud

In countries where the plant is already legal to produce, then the switch to hemp alternative building material should begin immediately.

Bamboo and Straw

Wood has long been a popular home building material, but not all plants are equally green. Bamboo has the quickest regrowth time of any plant, meaning that it can be replaced as quickly as it is cut down. It is strong and durable. Meanwhile, straw, when packed tightly, is a perfect eco-friendly insulation material. Together, this makes the most environmentally conscious wooden cabin.

In the debate of manufactured vs modular cabins, the latter tends to be preferred due to its rigidity and durability, while the former is more affordable. By constructing modular bamboo cabins, however, you are able to produce a long-lasting, energy efficient home at a much cheaper cost.

Reused Plastic Waste

The world purchases a million plastic bottles a minute or 480 billion a year. We need to seriously start thinking about how we can reduce our consumption of single use plastics, but also what to do with the waste in the meantime.

One thing that the bottles can be used for is the construction of houses. When filled with sand and stacked together, they form a durable and insulating wall. In some countries, this is being used as a way to bring affordable housing to those living in poverty. It is certainly a creative way to build homes without using more of the Earth’s precious resources.

Final Thoughts

There are so many alternatives to concrete out there. Governments and construction companies need to come together to move towards sustainable building practices. This will help to ensure that everyone has a safe place to call home, while recycling resources and cleaning the carbon dioxide out of the atmosphere.

A wide variety of wastes are generated during construction projects which may be classified into four categories – excavated wastes, demolition wastes, construction wastes and mixed wastes. Construction wastes are also known Construction and Demolition (C&D) wastes. Excavated materials is made up of soil, sand, gravel, rock, asphalt, etc. while demolition wastes is comprised by concrete, metal, roofing sheets, asbestos, brick, briquette, stone gypsum, wood material. Waste materials generated from construction activities are concrete, dry wall, plastics, ceramics tiles, metals, paper, cardboards, plastics, glass etc. In addition, mixed wastes, such as trash and organic wastes, are also produced in construction projects.

Almost 90 percent of construction wastes are inert or non-hazardous, and can be reused, reclaimed and recycled and reused. The non-recyclable, non-hazardous and hazardous waste materials constitute the remaining 10 percent. The non-inert materials include trees, green vegetation, trash and other organic materials while and the hazardous construction waste materials include contaminated soil, left over paints, solvent, aerosol cans, asbestos, paint thinners, striping paint, contaminated empty containers.

Sustainable management of construction wastes uses number of strategies and is based on the typical waste hierarchy: Avoid/ eliminate, reduce, reuse, recycle, treat and dispose.

Avoidance / Source Reduction

Avoidance or source reduction is considered as the best strategy for waste management and is the most economic way to reduce waste and minimise the environmental impacts of construction wastes. This can be done by avoiding use of hazardous materials such as asbestos-containing materials or chromated copper arsenate treated timber or through green purchasing of materials. This includes purchasing of non-toxic materials, pre-cut timbers and ordering materials of desired dimensions.

Reuse

Although source reduction and elimination are preferred options in the waste management hierarchy, it is always not possible to do so. In this case consider reuse, donation and salvage options to companies or people who need those. Reuse option lengthens the life of a material. Reuse strategy can be used in two ways.

Building Reuse – It includes reusing materials from existing buildings and maintaining certain percentages of building structural and non-structural elements such as interior walls, doors floor covering and ceilings.

Material Reuse – This is one of the most effective strategies for minimising environmental impacts which can be done by salvaging, refurbishing and reusing materials within the same building or in another building. Many of the exterior and interior materials can be recovered from existing buildings and reused in new ones. Such materials will include steel, walls, floor coverings, concrete, beams and posts, door frames, cabinetry and furniture, brick, and decorative items. Reuse of materials and products will help to reduce the demand for virgin materials and reduce wastes.

Recycle

There is very good potential to recycle many elements of construction waste. Recycling involves collecting, reprocessing and/ or recovering certain waste materials to make new materials or products. Often roll-off containers are used to transport the waste. Rubble can be crushed and reused in construction projects. Waste wood can also be recovered and recycled. Many construction waste materials that are still usable can be donated to non-profit organizations. This keeps the material out of the landfill and supports a good cause.

Treat and Dispose

This option should be considered after all other options are exhausted. The disposal of construction materials should be carried out in appropriate manner through an approved contractor. For examples, certain components of construction waste such as plasterboard are hazardous once landfilled. Plasterboard is broken down in landfill conditions releasing hydrogen sulfide, a toxic gas.